It is known that much of Northern and Eastern Canada is covered with virgin first and second growth of timber and pulp-producing trees which have been traditionally harvested by family concerns usually working during those months when the ground is sufficiently hard to walk on and when their farm work is slack. With the disappearance of the small family axe-wielding operation in favor of larger groups and companies, more mechanization of the tree harvesting business has been possible. As a consequence large tree harvesting devices have been manufactured that are capable of cutting and carrying the trunks of large trees on site. Much of the delimbing operations are still done by men wielding chain-saws, after the trunk is felled by machine, but the accident rate for delimbing with chain saws is very high and a better method is desirable.
Because of the relatively recent recession of the glaciers during the last Ice Age, the North is generally covered with an abundance of swampy wet terrain which is very fertile. Vast amounts of this ground has grown over in large very dense patches of Black Spruce. Due to the short growing periods of the northern summer, the rate of growth is slow in proportion to the more clement temperatures of Southern Canada and the United States. As a consequence large tree harvesting machines conceived and designed for conditions which exist in the south are ineffective and often immobilized by the soft, wet ground conditions in the north in the summer, and deep snow when the ground is frozen in the winter. The many pulp and paper, and saw mills, which exist in Northern Canada form a large forest industry. Many companies have their own woods department which cut and supply the logs required although most of the companies have several smaller contractors which supply wood. Some of the contractors have expanded to a point where they supply two or three concerns. All of these companies are still cutting and delimbing the majority of their wood by conventional chain saw methods. A few companies have acquired feller-buncher machines which simply cut the trees and lay them on the ground in bunches. However the delimbing which produces the highest number of chain saw accidents, is still done by a man wielding a chain saw.
This particular set of conditions--wet, soft terrain, deep snow, cold weather, high accident rates, high city wages, demanding physical work, not to mention an abundance of black flies, makes it increasingly difficult for the contractor to interest the average modern young man in cutting timber for a living. The contractors' biggest problem is obtaining the manpower required to do the work at a reasonable rate of pay. This is the most important factor in the contractors' desire to mechanize his forest operations. This has created a large demand for a tree harvester which could operate effectively at a profit. The tree harvesters presently used have been conceived for conditions other than found in the North. They are quite large in order to cut trees which grow much larger in other regions and they also have a different method of processing which inherently must produce a heavier larger machine. These machines delimb the trees while they are at their full length. This dictates the use of a mechanism which is made of delimbing knives capable of encircling the trunk and travelling the full length of the tree. This means the mechanism must extend and retract at least 50 to 60 feet, whether it be in horizontal or vertical position. This method dictates the shape of the mobile machine which must be large and heavy to support this mechanism. Such devices are useful in regions where the terrain is firm and capable of supporting high load concentrations. They are not economical under northern conditions.
The tree harvesters presently used are quite large in order to cut the largest trees and are therefore not capable of travelling over muskeg and soft ground or snow because of their weight and the weight of the large booms necessary for cutting and delimbing a tree while it is in an upright position. Such devices are very useful in virgin stands of timber such as are found on the West coast, but such large machines are not economical for the many small jobbers that operate in Eastern Canada whose principal source of harvestable material is spruce and aspen stands located on soft muskeg ground.